I supplied an over-volatge to BB and I think it's burned out.
Yeah... It's on my own mistake.. 
If I register RMA to BB.org can I receive repair service, too?
When I send email to Beagle Hospital co., I received email just
register the RMA.
But the important thing that I really want to ask is that how much is
it cost when I send it to BB hospital.
I am a undergraduate student, outside of USA. And I don't have a lot
of money to pay repair cost(shipping, duty and tax) when charge is
expensive.
In this situation, how much is it cost to send and receive the BBto
repair?
Request the RMA via the RMA request form. http://beagleboard.org/support/rma
As to cost, it all depends on how much is burned up, how high the voltage was, and how long it was exposed to the over voltage. Typically this is repaired at no cost as long as you are honest about what happened and don’t try to sneak one by. If the processor is burne dup, then there will be an addtional charge. You pay the shipping to the hospital and they pay the shipping back.
As to the shipping cost that depends on you. You can just mail it back. It takes longer, but does not cost as much. If you mark it correctly as a repair, there should be no duties and taxes.
Gerald